Lithium-ion battery

Abstract

A lithium-ion battery includes a positive electrode, which includes positive electrode mixture material containing positive electrode active material particles and conductive material, a negative electrode, which includes a negative electrode mixture material, and an electrolyte. The positive electrode active material particles include primary particles, a first particle aggregate of the primary particles cohered into a mass with a hollow portion having a diameter of less than 1 μm, and a second particle aggregate of the primary particles cohered into a mass with a hollow portion having a diameter of 1 μm or greater. When referring to the primary particles and the first particle aggregate as first particles, the first particles occupy 5% to 70% of the positive electrode active material particles. The positive electrode mixture material has a void percentage of 20% to 60%. The conductive material has an aspect ratio of 1:10 or greater.

What is claimed is: 
     
         1 . A lithium-ion battery, comprising:
 a positive electrode including a positive electrode mixture material containing positive electrode active material particles and a conductive material;   a negative electrode including a negative electrode mixture material; and   an electrolyte, wherein:   the positive electrode active material particles of the positive electrode mixture material include primary particles, a first particle aggregate of the primary particles cohered into a hollow mass with a hollow portion having a diameter of less than 1 μm, and a second particle aggregate of the primary particles cohered into a hollow mass with a hollow portion having a diameter of 1 μm or greater;   when referring to the primary particles and the first particle aggregate as first particles, a percentage of a total volume of the first particles with respect to a total volume of the positive electrode active material particles is 5% or greater and 70% or less;   the positive electrode mixture material has a void percentage of 20% or greater and 60% or less; and   the conductive material has an aspect ratio of 1:10 or greater.   
     
     
         2 . The lithium-ion battery according to  claim 1 , wherein the percentage of the volume of the first particles is 20% or greater and 50% or less. 
     
     
         3 . The lithium-ion battery according to  claim 1 , wherein the void percentage is 30% or greater and 50% or less. 
     
     
         4 . The lithium-ion battery according to  claim 1 , wherein the aspect ratio of the conductive material is 1:30 or greater. 
     
     
         5 . The lithium-ion battery according to  claim 1 , wherein a content percentage of the conductive material with respect to weight of positive electrode mixture material is 0.1 wt % or greater and 5 wt % or less. 
     
     
         6 . The lithium-ion battery according to  claim 1 , wherein the conductive material has an average diameter of 1 nm or greater and 100 nm or less.